Vijayan T
The introduced design method requires only the information of the port impedances, the coupling level, and the operational frequency. The design charts that give all the physical dimensions, including the length of the directional coupler versus frequency and different coupling levels, are given for alumina, Teflon, RO4003, FR4, and RF-60, which are widely used in microwave applications. Further work includes validation of analytical results using a planar electromagnetic simulation tool (IE3D) and experimental verification.